scribner



2 Sheets-Sheet v1.

(.No Model.)

C. E. SCRIBNBR. L NEEDLE PLUG rEsT SYSTEM EOE MULTIPLE. sWIToEEoAEDs..

Patented Deo. 1, 1896.

(No Model.) 2 sheetssheen 2.

' C.` E. SCRIBNER. NEEDLE PLUS TEST SYSTEM EOE MULTIPLE SWITGEBOAEDS.

No. 572,218.. Patnted 136051, 1896.

UNITED 'STATES' PATENT OFFICE,

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO TIIE IVESTERN ELECTRIC COMPANY, OF SAME PLACE.

NEEDLE-PLUG TEST SYSTEM FOR MULTIPLE SWlTCHBO-ARDS.

SPECIFICATION forming' part of Letters Patent No. 572,218, dated December 1, 1896. Application filed J'une l, 1888. Renewed February 24, lil-90. Serial No. 341,403. (No model.)

To all whom, t may concern: nected through the bell at the substation, as Be it known that LCHARLES E. SCRIBNER, a indicated by the dotted line, with ground at citizen of the United States, residing at Chithe substation in a manner well known and cago, in the county of Cook and State of 4Illiin common practice. Fig. 2 is a detailed sec- 5 5 nois, have invented a certain new and useful tional view of the needle test-plug inserted Improvement in a Needle-Plug Test System in a spring-jack switch. Fig. 3 is a diagram for' Multiple Switchboards, (Case No. 157,) of illustrative of the circuits oftwo telephonewhich the following is a full, clear, concise, lines connected with two boards of amultipleand exact description, reference being had to switchboard system, one of said lines being 6o the accompanying drawings, forming a part metallic and the other single, both lines, of this specification. however, being provided with terminal plugs My invention relates to a multiple-switchaccording to the single-cord system. board system of a telephone-exchange; and Like parts are indicated by similar letters its object is to provide a reliable and rapid of reference in the different figures. 6 5 test whereby it may be determined y at one Referring to Fig. l, it will be seen that the board whether a line called for 'is in use or needle test-plug c (for detail see Fig. 2) connot. sists of a metallic sleeve or shank provided My invention consists, first, in providing with the usual tip or ball and a central needle. in connection with a multiple-telephone-ex- The needle passes axially through the center 7o change switchboard system a battery norof the shank and is insulated therefrom. A mally connected with the lines after passing coiled spring presses the needle outward. through the switchboards and a switching de- When the plug is inserted in a spring-jack, vice for looping a telephone into the circuit the needle is forced back, the spring being at either of the boards to determine whether compressed sufficiently to permit of the plug 75 the said battery is or is not connected with being completelyinserted,so that the ball or the line, and, second, in providing a battery tip may lift the switch-lever from its normal connection at the central office with each line, contact-point, as shown in Fig. 2. The needle l and in testing apparatus so arranged that thusforms a yielding connection, insuring when a line tested is not in use current will always a good contact between the needle 8o be sent from the battery of the .line tested and the contact-point of the switch in which through the rheotome and one winding of an the plug may be inserted. The circuit b beinduction-coil, the other winding of the intween the needle and the shank of the plug, ductioncoil including the operators teleas shown in Fig. 1, is connected through one phone. Thus, when the test is made, if the vof the wires of an induction-coil c and the 85 line is free the tone or buzz caused by the vimain contacts of a rheotome dor other applibration of the rheotome in the battery-circuit, ance for interrupting the circuit. The ciror the click caused by bringing the telephone cuit-breaker d is constantly and automatinto the battery-circuit in case the rheotome ically operating, owing to the battery in its is omitted, will be heard in the telephone. own local circuit, to break the circuit ofthe 9o Vhen, however, a connection is kmade with cord connecting the sleeve and the tip of the any line, or if the terminal plug of any line test-plug. The other winding of the inducis lifted from its grounding-jack, its battery tion-coil is included in wire c, connected with connection will be open, and hence when a different sides of the operators vtelephone f. line in use is tested no sound will be heard The telephone-line circuit n n, whether me- 95 in the telephone. y tallic or grounded, is continued from the con- In Figure l I have shown a sect-ion of a multact-pieces of the last spring-jack to the differtiple switchboard and keyboard table in conent contactpieces of an ordinary terminal nection with my testing apparatus. I have 1oop-plugr. Plug r rests in a socket provided represented the substation, with which the with springs, which constitute the device gen- 10o telephone-line is connected, by a circle, one orally known as a grounding-jack. This side of the line being supposed to be conparticular grounding-jack 7L comprises a spring h', adapted to bear upon one side of the terminal plug, and when the latter is in vits socket to be forced against a contact h2 and away from a spring h3. When the terminal plug is removed from its socket, the spring 7L closes the spring h3 with such force as to separate the latter from the contact h4, against which it normally bears. A battery g, one pole of which is grounded, is shown connected to the contact h2, whence as long as the plug is in its socket it iinds circuit to the spring 7L', and thence by wire 'L' through the lever and through the .grounding-jack o4 and the' battery-o5 toground. The single telephoneline 19 is shown connected through its springjack switches q q of the different boards through annunciator q2, answering spring- Vjack g3, and -grounding-jack'q4 and battery 15 to ground. In this manner each telephoneline is normallyconnected with a battery or .other source of electricity.

As shown in Fig. 3, the terminal plugsrfr of the different lines are -s'hown kinserted in their sockets. In this position vthe grounding-jacks are brought in position to close'the battery to line, as above described. On lifting the terminalplug of any line the grounding-jack of the lineis changed so as to disconnect said line from battery at the grounding-jack. Moreover, whenever a connection is made with anyspring-jack of a -line the battery of that line will be cut off at the spring-jack where the. connection is made. This description has reference especially to the sin gle-cord system. The same result may be accomplished in various ways in doublecord systems; that is to-say, the circuits may be arranged so that the normal battery connection with any line will be opened whenever said line is in use.

In Fig. 1 I have shown apair of loop-plugs s s connected in such manner that when'on inserting either plug in the spring-jack of a line the operators telephone will belooped into the circuit of the line. The circuits and connections `specially shown between these plugs'andvthe operators outfit do not `form any part of my invention and are therefore disclaimed.

I have not deem cd it necessary to show the need-le-plug and its connections in Fig. 3. It is to be understood that each operator will be provided with a needle-plug vconnected with her telephone outfit, as described with respect to needle test-plug c of Fig.. I.

In order to make a test, the operator inserts the needle-pluginto the spring-j ack upon her board of the line called for in the manner shown in Fig. 2. If the line is not in use, the circuit of the battery normally connected with said line will be completed through the induction-coil and rheotome to the needle testplug thus inserted, and the operator listening at her telephone included in the circuit of the other winding of the induction-coil will hear the hum of the rheotome. This testingcircuit may be traced from ground through battery g to contact h2, thence through spring 7L', wire z', the contacts of the answering-jack la, the annunciator Z to the back contact of the iirst spring-jack m, thence-supposing this jack to be the one at which the test is being made-to the needle of the testing-plug, thence through the local circuit, including the rheotome and one winding of the induction-coil c, and to the sleeve of the testing- `plug c, thence to the line-spring of jack m and over the correspondin g side of the linecirc'uit to earth at the substation. If, however, the line tested is busy or if its terminal plug has been lifted, its normal battery connect-ion will be opened, and hence no sound will be heard by the operator on inserting'her needle test-"plug in the spring-jack of the line.

I prefer to' use the rheotomein connection with `the battery-circuit in order that the signal orsound caused in the telephone may be of a distinct and positive character. It is evident, however7 that my system would be operative without the rheotome, since the closing of the circuit through the telephone would cause a click or sound which would satisfactorily answer the purpose of indicating to the operator the presence of the battery.

Having thus described my invention, I claim as new and desire to secure by Letters Patent--A l. The combination with 'a telephone-line connected to ground vat the substation and with switches on two or more switchboards and through a grounding-jack and battery-to ground, of a test-plug inserted in a spring-jack of the line, said test-plu g being provided with two contacts or terminals, one of said terlninalsbeing connected with the lifted spring of the spring-jack and the other terminal being connected with the contact-point of the spring-jack,- a circuit vbetween said lterminals including one winding of an induction-coil and a rheotome or vibrator and a telephone included in the circuit of the other winding of the induction-coil7 whereby on listening at the telephone, a tone or lvibration may be heard, substantially as described.

2. The combination with `a telephone-line connected to earth at a substation and with spring-jack switches, one on each of two or more multiple switchboards, and from the switch onthe last-board through a-groundingjack and battery to ground, of the terminal plug of said line inserted in said groundingjack to close the connection of the line with IOO IIO

said battery, a switching device including one winding of an induction-coil and the main contacts of a rheotome or vibrator, which switching device on being inserted in a springjack of the line loops said winding of the induction-coil and rheotome into the circuit and a telephone connected in a circuit with the other winding of the induction-coil, substantially as described.

3. The combination with the needle testplug provided with an insulated contact-piece and aneedle-point, and said contact-piece and point constituting the terminals of a rheotome and one winding of an induction-coil included in circuit between said terminals, a telephone included in circuit with the other winding of the induction-coil, a telephone-line including two or more switches and a test-battery, whereby on inserting the test-plug in one of the spring-j ack switches of the line it maybe determined whether or not said line is open at another spring-jack of the line.

4. In a test system for telephone-switchboards, a normally-closed circuit including a source of current for each line, means for making connection with the line at any of several points and simultaneously interrupting the said circuit there, a test-indicating instrument, and a testing-plug connected therewith adapted to break the said circuit and loop the said instrument into the circuit, whereby the test instrument is caused to respond when the line is free, substantially as described.

5. The combination with a telephone-line extending to the central station and connected through spring-jacks upon the several switchboards, of a source of electricity normally in circuit with the line, but adapted to be disconnected therefrom when connection is made with the line, a loop-plug adapted to be inserted into a spring-jack of the line, and a signaling device connected between the terminals of the loop-plug adapted to respond when said source of electricity is connected in circuit but to remain irresponsive when said source of electricity is disconnected from the line, substantially as described.

6. The combination with a telephone-line grounded at each terminal, of spring-jack switches included serially in the line said spring-jack switches having separable contacts, and a source of testing-current normally connected with the said telephone-line but adapted to be disconnected therefrom when the line is switched for conversation, a plug adapted for insertion into a spring-j ack switch having contact-pieces adapted to register with. the separated contact-points of the springj ack, respectively, and a signaling instrument in a circuit between the contact-pieces of the plug, substantially as described.

7. The combination with a telephone-line, of spring-j ack switches having separable contacts included serially in the line-circuit, a ground connection with the line before the iirst spring-jack, and another ground connection including a source of testing-current after the last spring-jack in the series, a loopplug adapted for insertion into any springjack to register with the separated contacts of the spring-j ack, and a signaling instrument included in a circuit between the contactpieces of the plug, substantially as described.

In witness whereof I hereunto subscribe my 7 5 name this 12th day of March, A. D. 1888.

CHARLES E. SCRIBNER. lVitnesses:

CHAs. G. HAWLEY, CHAs'. C. WooDwoRrH. 

